The present invention relates to a filter sealing device for sealing a clearance between a ceiling frame and filter frames placed thereon for use in clean rooms, for example, of semiconductor manufacturing plants, pharmaceutical plants and hospitals, biologically clean rooms, etc., and more particularly to a sealing device suitable for superhigh efficiency filters such as HEPA filters and ULPA filters.
The ceiling portion of such a clean room has a ceiling frame which comprises horizontal beams arranged lengthwise and crosswise and defining openings therebetween, and a plurality of filters arragned on the ceiling frame for the respective openings. Super-high efficiency filters such as those mentioned above are often used for clean rooms of higher grade.
While the filter is fixed to the ceiling frame by a filter frame placed thereon, it is necessary to prevent leakage of air through a clearance between the frames. Especially in the case of superhigh efficiency filters which offer great resistance and produce a great pressure difference, a great air leak will occur unless the clearance is sealed off reliably.
To preclude such leakage of air from between the ceiling frame and the filter, a sealing material is conventionally provided between the upper face of the ceiling frame and the lower edge of the filter frame as disclosed, for example, in Examined Japanese Utility Model Publication No. 31130/1990.
The sealing material is applied in situ, therefore requires labor and is likely to permit an air leak if applied improperly to result in impaired filtration. Moreover, the sealing material is likely to release a solvent gas and harden during use, failing to serve the desired sealing function.
Further when there arises a need to remove the filter from the ceiling frame during use for cleaning or replacement, the sealing material must be cut off by a troublesome procedure, and the cumbersome work need to be repeated again for the installation of filter.
Another problem is also encountered in that air is liable to leak from the beam joints of the ceiling frame.